Estimating the prevalence and correlates of pain among people living with HIV who use unregulated drugs in a Canadian setting.

Although prevalent among people living with human immunodeficiency virus (HIV) (PLWH) and people who use unregulated drugs (PWUD), pain and its possible links to substance use patterns and engagement in HIV treatment remains poorly characterized. We sought to evaluate the prevalence and correlates of pain among a cohort of PLWH who use un-regulated drugs. Between December 2011 and November 2018, 709 participants were recruited, and data were analyzed using generalized linear mixed-effects (GLMM). At baseline, 374 (53 percent) individuals reported moderate-to-extreme pain in the previous 6 months. In a multivariable model, pain was significantly associated with nonmedical prescrip-tion-opioid use (adjusted odds ratio (AOR) = 1.63, 95 percent confidence interval (CI): 1.30-2.05), nonfatal overdose (AOR = 1.46, 95 percent CI: 1.11-1.93), self-managing pain (AOR = 2.25, 95 percent CI: 1.94-2.61), requesting pain medication in the previous 6 months (AOR = 2.01, 95 percent CI: 1.69-2.38), and ever being diagnosed with a mental illness (AOR = 1.47, 95 percent CI: 1.11-1.94). Establishing accessible pain management interventions that address the complex intersection of pain, drug use, and HIV-infection has potential to improve quality of life outcomes among this population.

Perceived Mistreatment in Health Care Settings and its Relationship with HIV Clinical Outcomes in HIV-positive People who Use Drugs in Vancouver, Canada.

People living with HIV (PLWH) often experience stigma and discrimination by health care professionals. We investigated the prevalence of perceived mistreatment in health care settings and its associations with HIV clinical outcomes and health care-seeking behaviour using data from a long-running prospective cohort of PLWH who use drugs. Of the 857 participants included, 19% reported at least one instance of perceived mistreatment during the study period. In adjusted longitudinal analyses, perceived mistreatment was positively associated with not being on ART in the same follow-up period, and participants who reported perceived mistreatment were less likely to report seeing a physician in the subsequent follow-up period. Daily use of injection drugs was positively associated with reporting perceived mistreatment. These findings demonstrate the implications of negative health care interactions in a population that must consistently engage with the health care system, and the need for stigma-reducing educational interventions for health care professionals.

Prevalence and longitudinal correlates of recent exposure to fentanyl among HIV-positive people who use unregulated drugs during a community-wide overdose crisis.

The United States and Canada are experiencing an opioid overdose crisis driven largely by exposure to fentanyl (a potent synthetic opioid), with little known about fentanyl exposure among HIV-positive people who use unregulated drugs (PWUD). We sought to estimate the prevalence and correlates of fentanyl exposure among a community-recruited sample derived from a prospective cohort study of HIV-positive PWUD in Vancouver, Canada. Generalized linear mixed-effects analyses were used to identify longitudinal factors associated with a fentanyl-positive urine drug screen test. Between June 2016-November 2017, 456 participants were recruited and contributed 1007 observations. At baseline, 96% of participants were ART-exposed, 72% had an HIV viral load (VL) <50 copies/mL and 21% had a fentanyl-positive test. Longitudinally, fentanyl-positive tests were characterized by: younger participant age (Adjusted Odds Ratio [AOR] = 0.45), recent non-fatal overdose (AOR = 2.30), engagement in opioid agonist therapy (AOR = 1.91), and at least daily heroin injection (AOR = 11.27). CD4+ cell count was negatively associated with fentanyl urine positivity (AOR = 0.92) (all p < 0.05). We identified several risk factors for overdose linked to fentanyl exposure among this sample, although no link with HIV treatment engagement or detectable HIV VL. Innovative strategies are needed to reduce the harmful effects of the contaminated unregulated drug supply experienced by PWUD.

SVM Optimization for Brain Tumor Identification Using Infrared Spectroscopic Samples.

The work presented in this paper is focused on the use of spectroscopy to identify the type of tissue of human brain samples employing support vector machine classifiers. Two different spectrometers were used to acquire infrared spectroscopic signatures in the wavenumber range between 1200⁻3500 cm-1. An extensive analysis was performed to find the optimal configuration for a support vector machine classifier and determine the most relevant regions of the spectra for this particular application. The results demonstrate that the developed algorithm is robust enough to classify the infrared spectroscopic data of human brain tissue at three different discrimination levels.

Longer duration of homelessness is associated with a lower likelihood of non-detectable plasma HIV-1 RNA viral load among people who use illicit drugs in a Canadian setting.

Homelessness is common among people who use drugs (PWUD) and, for those living with HIV/AIDS, an important contributor to sub-optimal HIV treatment outcomes. This study aims to investigate the relationship between the duration of homelessness and the likelihood of plasma HIV-1 RNA viral load (VL) non-detectability among a cohort of HIV-positive PWUD. We used data from the ACCESS study, a long-running prospective cohort study of HIV-positive PWUD linked to comprehensive HIV clinical records including systematic plasma HIV-1 RNA VL monitoring. We estimated the longitudinal relationship between the duration of homelessness and the likelihood of exhibiting a non-detectable VL (i.e., <500 copies/mL plasma) using generalized linear mixed-effects modelling. Between May 1996 and June 2014, 922 highly active antiretroviral therapy-exposed participants were recruited and contributed 8188 observations. Of these, 4800 (59%) were characterized by non-detectable VL. Participants reported they were homeless in 910 (11%) interviews (median: six months, interquartile range: 6-12 months). A longer duration of homelessness was associated with lower odds of VL non-detectability (adjusted odds ratio = 0.71 per six-month period of homelessness, 95% confidence interval: 0.60-0.83) after adjustment for age, ancestry, drug use patterns, engagement in addiction treatment, and other potential confounders. Longer durations of episodes of homelessness in this cohort of HIV-positive illicit drug users were associated with a lower likelihood of plasma VL non-detectability. Our findings suggest that interventions that seek to promptly house homeless individuals, such as Housing First approaches, might assist in maximizing the clinical and public health benefits of antiretroviral therapy among people living with HIV/AIDS.